The present invention relates to an electrically heated smoking system for receiving an aerosol-forming substrate. In particular, the present invention relates to an electrically heated smoking system for receiving an aerosol-forming substrate, in which the aerosol-forming substrate is a liquid.
A number of prior art documents, for example U.S. Pat. No. 5,060,671 (commonly assigned, the entire contents of which are incorporated herein by this reference thereto), U.S. Pat. No. 5,388,594 (commonly assigned, the entire contents of which are incorporated herein by this reference thereto), U.S. Pat. No. 5,505,214 (commonly assigned, the entire contents of which are incorporated herein by this reference thereto), U.S. Pat. No. 5,591,368 (commonly assigned, the entire contents of which are incorporated herein by this reference thereto), WO 2004/043175 (commonly assigned, the entire contents of which are incorporated herein by this reference thereto), EP-A-0 358 002 and WO 2007/131449, disclose electrically operated smoking systems, having a number of advantages. One advantage is that they significantly reduce sidestream smoke, while permitting the smoker to selectively suspend and reinitiate smoking.
Other prior art documents, such as EP-A-0 295 122, EP-A-1 618 803 and EP-A-1 736 065, disclose electrical smoking systems which use a liquid as the aerosol-forming substrate. The liquid may be contained in a cartridge which is receivable in a housing. A power supply, such as a battery, is provided, connected to a heater to heat the liquid substrate during a puff, to form the aerosol which is provided to the smoker.
The electrically heated smoking systems of the prior art, including those described above, do have a number of advantages, but there is still room for improvement. It is therefore an object of the invention to provide an improved electrically heated smoking system.